how to sort an array of arrays based on other array JS

Question

array or arrays

var items = [
    ['alice','bob', 'emma', 'isabella'],
    ['emma','sofia', 'alice', 'bob'],
    ['bob','emma', 'alice']
];

how to map items in concrete order ['alice','emma','bob', ..other]

every array can have items like alice, bob and emma and other

What do you mean by "*map items in concrete order*"? Are you asking to `.sort()` them? — Bergi, Aug 31 '20 at 21:19
items.map((item) => ( //here item i want to be in order alice, bob, emma, others — Alex, Aug 31 '20 at 21:21
And how is that order chosen? Is it an alphabetical order, a random made-up one, the one of the first array in `items`? — Bergi, Aug 31 '20 at 21:22
you want sorted the item array for the first occurence in the inner-array or you want the name-arrays are sorted? — Sascha, Aug 31 '20 at 21:23
Add commas (`,`) after all-but-last inner arrays. Then, use this: `items.map(item=>item.sort())`. — iAmOren, Aug 31 '20 at 21:26
Javascript is not like Haskell or Prolog, It will not try to match literals. — Dominique Fortin, Aug 31 '20 at 21:29
@ iAmOren sort will order alphabetically, but how to order by given list — Alex, Aug 31 '20 at 21:29
so if the input is `[1, 2, 3, 4, 5]`, then defines `concrete` order is `[3, 2, 4, 5]`, then the output will be `[3, 2, 4, 5, 1]`? — Sphinx, Aug 31 '20 at 21:36
@Bergi in case we speak only about an array, for e.g `['emma','sofia', 'alice', 'bob']` how to reorder it in `['alice','emma','bob','sofia']`, other e.g. `['bob','sofia', 'emma', 'alice']` reorder in `['alice','emma','bob','sofia']` — Alex, Aug 31 '20 at 21:38
@Sphinx yes, like your example, but only with strings instead of numbers — Alex, Aug 31 '20 at 21:40
Use sort() and subtract reference index a from reference index b. Assumes you have a preordained order for all items included in your arrays — charlietfl, Aug 31 '20 at 21:42
@Alex So [this](https://stackoverflow.com/q/13304543/1048572) is what you were looking for? — Bergi, Aug 31 '20 at 21:46
the link @Bergi provided should give you some idea. but if the order of `other` elements is not matter, probably you will want to try this one: `function sort(src, concrete) { let orderDict = concrete.reduce((pre, cur, index) => { pre[cur] = index + 1 return pre }, {}) return src.map(items => { return items.sort((a, b) => { let t1 = orderDict[a] || 9999999 let t2 = orderDict[b] || 9999999 return t1 - t2 }) }) }` — Sphinx, Aug 31 '20 at 21:52

Sascha · Answer 1 · 2020-08-31T22:16:02.840

1

var items = [
    ['alice','bob', 'emma', 'isabella'],
    ['emma','sofia', 'alice', 'bob'],
    ['bob','emma', 'alice']
];

const NAME =  ['alice','bob', 'emma'];
let res = [];

items.forEach(names => {
    names.sort((a,b) => {
        indA = NAME.indexOf(a);
        indB = NAME.indexOf(b);
        if (indA!=-1)
            return (indB!=-1) ? indA-indB : -1;
        else return (indB!=-1) ? 1 : 0;
    });
    res.push(names);
});

console.log(res);

edited Aug 31 '20 at 22:16

answered Aug 31 '20 at 21:42

Sascha

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You should return `0` if both `indA` and `indB` are `-1`, otherwise this is not a consistent comparison function. Easiest done by `return (indA==-1) - (indB==-1) || indA - indB;` – Bergi Aug 31 '20 at 21:49
1

@Bergi - You are right. Thanks, I corrected it. – Sascha Aug 31 '20 at 22:17

how to sort an array of arrays based on other array JS

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